JP6601134B2 - 4-cycle multi-cylinder engine - Google Patents

Description

  The present invention relates to a four-cycle multi-cylinder engine that is typically suitable for motorcycles and the like.

In order to improve steering stability in a motorcycle, it is necessary to arrange the axis of the crankshaft at an optimum position with respect to the position of the front wheel. When the cylinder is tilted forward with respect to the crankshaft position, the cylinder head protrudes forward, so if you want to ensure proper clearance between the radiator, exhaust pipe, etc. and the front wheels, the axis of the crankshaft Must be placed backwards. As it is, it becomes difficult to set the axis of the crankshaft to the optimum position with respect to the position of the front wheel, and as a result, it becomes difficult to improve the steering stability.
For example, Patent Document 1 discloses an example of an engine having a cylinder-integrated upper crankcase and in which the cylinder is disposed with a moderate forward tilt.

  As a conventional measure, there is a method in which the cylinder head is moved backward by rotating the entire engine rearward around a drive shaft (output shaft). As a result, the center shaft of the crankshaft is not disposed rearward, and an appropriate clearance between the radiator and the front wheel is to be secured.

JP 2010-174776

However, in the conventional engine, when the whole engine is rotated backward, the vertical positions of the crankshaft, the cylinder head, and the like are increased, and on the contrary, it becomes an obstacle to steering stability. In addition, the space for arranging the air cleaner box and the fuel tank disposed above the engine is restricted, and there arises a problem that it is difficult to secure the capacity thereof.
Further, as another countermeasure method, it can be dealt with by extending the wheel base, but in that case, there are problems such as an increase in vehicle weight and an increase in the minimum turning radius.

  In view of such circumstances, an object of the present invention is to provide a four-cycle multi-cylinder engine that effectively improves steering stability while ensuring an appropriate arrangement relationship with other components.

A four-cycle multi-cylinder engine according to the present invention includes a crankcase that is divided into an upper case and a lower case, a cylinder block that is integrated with the crankcase, a crankshaft that is pivotally supported on a mating surface of the crankcase, A four-cycle multi-cylinder engine having a shift input shaft, wherein an extension line connecting the respective center axes of the crankshaft and the shift input shaft and a cylinder axis line of the cylinder block intersect at an acute angle in a side view of the engine. Further, the cylinder block is arranged to be inclined rearward with respect to a perpendicular line passing through the crankshaft from the extension line .

  Further, in the four-cycle multi-cylinder engine of the present invention, the lower surface of the cylinder block, on the lower side of the water jacket, with respect to the surface perpendicular to the mating surface of the crankcase from the profile of the mating surface of the cylinder head, A concave shape is provided on the cylinder axis side of the cylinder block, and a starter motor is disposed in the concave shape.

  In the four-cycle multi-cylinder engine of the present invention, the concave shape is provided substantially at the center in the engine width direction.

  The four-cycle multi-cylinder engine of the present invention is characterized in that a breather chamber is provided integrally with the upper case behind the starter motor.

  According to the present invention, since the cylinder block is inclined rearward, the distance between the front wheel and the crankshaft can be appropriately set while maintaining the height of the crankshaft, and the steering stability of the vehicle is improved. It becomes possible. Since the height position of the crankshaft is not substantially changed, the layout can be performed without affecting the arrangement relationship with other parts. Further, by arranging the cylinder block to be inclined rearward, the exhaust pipe, the radiator and the like can be arranged close to the engine side, and the wheel base can be effectively shortened.

1 is a side view of a motorcycle according to an embodiment of the present invention. It is a front view which shows the engine periphery mounted in the vehicle body in embodiment of this invention. It is a left view of the engine in the embodiment of the present invention. It is a right view which shows the state which removed the clutch cover from the crankcase in embodiment of this invention. It is the top view which looked at the mating surface of the lower case in embodiment of this invention from upper direction. It is sectional drawing which shows typically the structure by which the cylinder block in embodiment of this invention is inclined and arrange | positioned back. It is a back perspective view of the crankcase in the embodiment of the present invention.

Hereinafter, preferred embodiments of a four-cycle multi-cylinder engine according to the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing a configuration example of a main part of a motorcycle 100 as an application example of the present invention, and FIG. 2 is a front view showing the periphery of an engine mounted on a vehicle body. First, the configuration of the main part of the motorcycle 100 will be described with reference to FIG. 1 and FIG. In the drawings used in the following description, including FIG. 1, the front of the vehicle is indicated by an arrow Fr, the rear of the vehicle is indicated by an arrow Rr, and the lateral right side of the vehicle is indicated by an arrow R as necessary. The left side is indicated by an arrow L.

  1 and 2, a motorcycle 100 has a body frame 101 made of steel or aluminum alloy, and the body frame 101 supports components or parts such as an engine. Two front forks 103 are provided at the front of the body frame 101 and are supported by a steering head pipe 102 so as to be turnable left and right. A handle bar is fixed to the upper end of the front fork 103 via a steering bracket. A front wheel 104 is rotatably supported on the lower portion of the front fork 103, and a front fender is attached so as to cover the upper portion of the front wheel 104.

  The vehicle body frame 101 is integrally coupled to the rear portion of the steering head pipe 102, branches into a bifurcated pair of left and right sides, and extends from the steering head pipe 102 while being widened rearward and downward. It is configured as a so-called twin spar type frame composed of 101A and a pivot frame portion 101B which is welded to the main frame portion 101A and extends rearward and downward. The main frame portion 101A and the pivot frame portion 101B are coupled to each other and have a three-dimensional structure in which a space is formed as a whole, and the engine 10 is mounted on the vehicle body frame 101 inside the space.

  A swing arm is coupled via a pivot shaft 105 so as to be swingable in the vertical direction in the middle in the vertical direction of the pivot frame portion 101B of the body frame 101. A rear wheel 106 (partially abbreviated by a two-dot chain line) is rotatably supported at the rear end of the swing arm. A rear shock absorber is mounted between the vehicle body frame 101 and the swing arm. In particular, the lower end side of the rear shock absorber is connected to both the vehicle body frame 101 and the swing arm via a link mechanism. A driven sprocket is pivotally attached to the rear wheel 106, and a power transmission chain is wound between the drive sprocket on the engine 10 side and the driven sprocket of the rear wheel 106. Engine power is transmitted from the drive sprocket to the driven sprocket via the chain, thereby driving the rear wheel 106 to rotate. A rear fender covering the vicinity of the front upper portion is provided in the immediate vicinity of the rear wheel 106.

Further, from the vicinity of the rear part of the body frame 101 to the upper part of the rear wheel 106, the seat rail 107 extends rearward while being inclined moderately rearward, and the seat (seat seat) is supported by the seat rail 107. A fuel tank is mounted on the front side of the seat.

  In the exterior of the vehicle, the front and left and right side portions of the vehicle mainly have cowlings (hereinafter simply referred to as cowls). In this example, the upper cowl, body cowl, and under cowl are integrated to cover the front of the vehicle, Covered by side cowl. A seat cowl is attached around the seat at the rear of the vehicle.

  As shown in FIGS. 1 and 2, the engine 10 is mounted and supported by the vehicle body frame 101 at a substantially vehicle central portion of the motorcycle 100. In this embodiment, the engine 10 is a water-cooled multi-cylinder four-cycle gasoline engine. The engine 10 is a parallel multi-cylinder engine in which cylinders are arranged side by side in the left-right direction (vehicle width direction). Specifically, the engine 10 is a parallel 4-cylinder engine. In the description, they are simply described as “# 1”). FIG. 3 is a left side view of the engine 10 according to the present embodiment. Referring also to FIG. 3, a cylinder block 13 above a crankcase 12 that houses a crankshaft (crankshaft) 11 that is horizontally supported horizontally. The cylinder head 14 and the cylinder head cover 15 are integrally connected so as to overlap each other, and an oil pan 16 is attached to the lower portion of the crankcase 12. It should be noted that the cylinder axis Z of the engine 10 is disposed with a moderate inclination forward. The engine 10 is suspended and supported by a plurality of engine mounts (engine suspension portions) so as to be integrally coupled and supported on the inner side of the body frame 101, and acts as a rigid member of the body frame 101 by itself.

  A transmission case 17 is integrally formed at the rear portion of the crankcase 12, and a counter shaft and a plurality of transmission gears, which will be described later, are disposed in the transmission case 17. The power of the engine 10 is finally transmitted from the crankshaft 11 through the transmission to the drive sprocket which is the output end thereof, and the drive sprocket passes the rear wheel 106 (FIG. 1) through the power transmission chain as described above. Rotating drive.

  Note that the crankcase 12 and the transmission case 17 are integrally connected to each other to constitute a casing assembly of an engine unit including the engine 10 as a whole. A plurality of auxiliary machines including a starter motor for starting the engine, a clutch device, and the like, which will be described later, are mounted or coupled at appropriate positions of the casing assembly, and the entire engine unit including these is supported by the vehicle body frame 101.

  The engine 10 further includes an air intake system that supplies air (intake air) and an air-fuel mixture supplied from an air cleaner and a fuel supply device, an exhaust system that exhausts exhaust gas after combustion from the engine 10, and the engine 10 is cooled. A cooling system that lubricates and a lubrication system that lubricates the movable part of the engine 10 and a control system (ECU; Engine Control Unit) that controls the operation thereof are attached. By controlling the control system, a plurality of functional systems cooperate with the above-mentioned auxiliary machines and the like, and thereby smooth operation of the entire engine unit is performed.

  Each functional system will be described. First, an intake port (intake port) is opened on the rear side of the cylinder head 14 in each cylinder in the intake system, and a throttle body is connected to the intake port via an intake pipe (intake pipe). . The throttle body is provided with a throttle valve that opens and closes an intake flow path or passage formed in the throttle body according to the accelerator opening, and the flow rate of air supplied from the air cleaner is controlled. In this example, the throttle valve shaft of each cylinder is coaxially arranged, and has a valve drive mechanism for driving the throttle valve shaft mechanically, electrically or electromagnetically.

  On the other hand, each throttle body is provided with an injector for fuel injection downstream of the throttle valve, and fuel in the fuel tank is supplied to these injectors by a fuel pump. In this case, each injector is connected to a delivery pipe laid horizontally in the vehicle width direction on the upper side, and fuel is distributed from the delivery pipe connected to the fuel pump. Each injector injects fuel into the intake passage in the throttle body at a predetermined timing under the control of the control system described above, whereby a mixture of a predetermined air-fuel ratio is supplied to the cylinder block 13 of each cylinder.

Next, in each exhaust system, an exhaust port (exhaust port) is opened in front of the cylinder head 14 in each cylinder, and an exhaust pipe (exhaust pipe) 18 is connected to the exhaust port. The exhaust pipe 18 of each cylinder extends downward from the exhaust port, and merges and integrates below the crankcase 12. The exhaust pipe 18 extends rearward, and a muffler 19 is attached to the rear end thereof.
In this case, the exhaust pipe 18 of the # 1 cylinder and the exhaust pipe 18 of the # 2 cylinder join at the joining part 20, and the exhaust pipe 18 of the # 3 cylinder and the exhaust pipe 18 of the # 4 cylinder join at the joining part 21. Further, when the merging portion 20 and the merging portion 21 merge with each other, the four exhaust pipes 18 of the # 1 to # 4 cylinders gather in a single collecting pipe 22 substantially at the lower left of the oil pan 16. The collecting pipe 22 is connected to the muffler 19 via the connection pipe 23.

  In the cooling system, a water jacket is formed around the cylinder block 13 and the cylinder head 14 so that cooling water circulates. A radiator 24 which is a heat exchanger for cooling the cooling water fed to the water jacket is provided. The radiator 24 dissipates the heat of the cooling water flowing through the interior by applying the traveling wind. In this example, the radiator 24 has a substantially horizontally long rectangular shape as viewed from the front, as shown in FIG. From the vicinity of the lower portion of the steering head pipe 102 to the vicinity of the front side of the exhaust pipe 18 in front of the cylinder block 13, the rear end of the steering head pipe 102 is disposed so as to be inclined moderately to the rear. The cylinder block 13 of the engine 10 is substantially covered with a radiator 24 in a front view. The radiator 24 is supported at an appropriate position using the body frame 101 or the like.

  In this example, in the cooling system, as shown in FIG. 3, a water pump 25 is provided on the left side wall of the crankcase 12 so as to be driven in conjunction with, for example, an oil pump built in the crankcase 12. The water pump 25 and the water jacket are connected to each other by a cooling water hose, and the water pump 25 and the radiator 24 are connected to each other by another cooling water hose. Cooled cooling water is supplied from the radiator 24 to the water pump 25 via a cooling water hose. The water pump 25 discharges the cooling water cooled by the radiator 24 and circulates the water jacket, thereby cooling the engine. The cooling water that has circulated in the water jacket is fed to the radiator 24 via the cooling water hose. The radiator 24 cools the cooling water supplied from the engine 10 and supplies it again to the water pump 25 through the cooling water hose, and the cooling water circulation is repeated in the cooling system.

  Further, a lubricating system is configured to supply lubricating oil to the movable parts of the engine unit and lubricate them. This lubrication system includes a valve gear configured around the crankshaft 11 and in the cylinder head 14, and a cam chain, a transmission, and the like that connect them. In the present embodiment, an oil pump that is driven by using the rotational force of the crankshaft 11 directly or indirectly as a drive source is incorporated in the crankcase 12 with respect to the lubrication system. A trochoid pump or the like is used as the oil pump, and the lubricating oil sucked up from the oil pan 16 by this oil pump is supplied to the lubricating system. An oil filter 26 (FIG. 1) is attached to the front lower portion of the crankcase 12, and the lubricating oil is purified by the oil filter 26 before being supplied to the lubrication system.

  A specific configuration example around the crankcase 12 will now be described with reference to FIGS. 4 and 5 as well. 4 is a right side view showing a state in which the clutch cover 27 (see FIG. 1) is removed from the crankcase 12, and FIG. 5 is a mating surface 12A of the lower case 29 among the upper case 28 and the lower case 29 constituting the crankcase 12. It is the top view which looked at from the upper part. In this embodiment, the crankcase 12 is divided into upper and lower parts by an upper case 28 and a lower case 29, and the crank chamber 30 is formed by closing both of them. In this case, the cylinder block 13 is integral with the crankcase 12, that is, integrally formed with the upper case 28. Further, the crankshaft 11 and the countershaft 31 that is a transmission input shaft are pivotally supported by the mating surface 12A of the crankcase 12. The mating surface 12A is set so as to incline backward as shown in FIG.

  In the crank chamber 30 of the crankcase 12, the crankshaft 11 and a crank web 32 integrated with the crankshaft 11 are arranged on the mating surface 12 </ b> A via journal bearings 34 with a plurality (five in this example) of journal portions 33. And is pivotally supported. A connecting rod 35 is connected between the crank webs 32 corresponding to the cylinders via a crank pin. A piston is pivotally attached to the tip (small end) of the connecting rod 35 via a piston pin, and the piston reciprocates up and down in the cylinder bore of the cylinder block 13. The crankshaft 11 is rotationally driven by the reciprocating operation of the piston.

  In the transmission case 17, the countershaft 31 is rotatably supported on the mating surface 12 </ b> A in parallel with the rear of the crankshaft 11. The counter shaft 31 is supported via a bearing 36 and the like. One end (right side) of the crankshaft 11 is provided so as to protrude into the clutch chamber, and the primary drive gear 37 is pivotally attached to this end. On the other hand, a primary driven gear 38 that meshes with the primary drive gear 37 is attached to one end (right side) of the counter shaft 31, and the counter shaft 31 can be driven to rotate by rotation of the crankshaft 11. A clutch device 39 is configured at an end portion of the counter shaft 31 that protrudes toward the clutch chamber, and the clutch device 39 connects and disconnects the power between the crankshaft 11 and the counter shaft 31. The clutch shaft of the clutch device 39 is arranged coaxially with the counter shaft 31.

  Further, in the transmission case 17, the counter shaft 31 constitutes a part of a transmission (transmission) accommodated in the transmission case 17. A drive shaft 40 is disposed substantially below the counter shaft 31, and a plurality of transmission gears are arranged in a row on the counter shaft 31 and the drive shaft 40. These transmission gears are selectively set in meshing relationship by a gear shift device, thereby obtaining a desired gear ratio of the transmission. The power of the engine 10 is finally transmitted from the crankshaft 11 through a transmission to a drive sprocket 41 (see FIG. 3) attached to the shaft end of the drive shaft 40. As described above, the drive sprocket 41 rotationally drives the driven sprocket, and hence the rear wheel 106, through the power transmission chain.

  Now, in the engine 10 having the above-described configuration, in the present invention, as shown in FIG. Are arranged so as to incline backward so that they intersect at an acute angle θ. As shown in FIG. 6, the extension line M is on the mating surface 12A of the upper case 28 and the lower case 29 of the crankcase 12, and the cylinder P is perpendicular to the perpendicular line P passing through the crankshaft 11 from the mating surface 12A. The axis Z is set to be tilted backward.

  Further, as shown in FIG. 6, on the rear surface of the cylinder block 13, below the water jacket 42, a surface perpendicular to the mating surface 12A of the crankcase 12 from the profile of the mating surface 13A with the cylinder head 14 (vertical surface). In contrast to S), a concave shape 43 is formed on the cylinder axis Z side of the cylinder block 13. As shown in FIG. 7, the starter motor 44 is arranged in the concave shape 43. As described above, the cylinder axis Z is rearwardly inclined and intersects the extended line M connecting the crankshaft 11 and the countershaft 31 at an acute angle θ, so that the rear side of the cylinder block 13 is concave with respect to the vertical plane S.

In the above case, the concave shape 43 of the cylinder block 13 is provided in the center in the engine width direction as shown in FIG. The concave shape 43 substantially corresponds to the # 2 cylinder and the # 3 cylinder.
Referring also to FIG. 3, a breather chamber 45 is provided behind the starter motor 44 so as to be integrated with the upper case 28. The breather chamber 45 has a breather chamber cover 46 (FIG. 3). The introduced blow-by gas is separated into gas and liquid, and the separated gas is returned to the intake system.

  Here, referring to FIG. 5, the output shaft 44 a of the starter motor 44 is disposed in the left-right direction, that is, in parallel with the crankshaft 11 and extends to the right, and between the output shaft 44 a and the crankshaft 11, It meshes with a torque limiter 47 mounted on a driving force transmission shaft 48 extending in parallel. The torque limiter 47 is configured to transmit only the torque from the starter motor 44 to the crankshaft 11 side and to block the torque from the crankshaft 11 side to the starter motor 44 side. The torque limiter 47 is connected to the crankshaft 11 via a plurality of idle gears 49. In this case, the idle gear 49A at the final stage meshes with a one-way clutch 50 that is attached to the right end of the crankshaft 11. When the starter motor 44 is operated, the crankshaft 11 is forcibly rotated via the torque limiter 47, the idle gear 49, and the like, whereby the engine 10 can be started.

  In the engine 10 of the present invention, the extension line M and the cylinder axis Z of the cylinder block 13 intersect at an acute angle θ, that is, the cylinder block 13 is inclined rearward, so that the front wheel is maintained while maintaining the height of the crankshaft 11. The distance between 104 and the crankshaft 11 can be set appropriately. That is, the distance between the front wheel 104 and the crankshaft 11 can be effectively reduced, and the steering stability can be improved. In this case, since the height position of the crankshaft 11 does not substantially change, it does not interfere with an air cleaner box, a fuel tank, or the like disposed above the engine 10, that is, affects the positional relationship with other components. Can be laid out. Further, the cylinder block 13 is tilted rearward so that the exhaust pipe 18 and the radiator 24 can be disposed closer to the engine 10 side, and the wheelbase can be effectively shortened.

  Further, a concave shape 43 is provided below the water jacket 42 on the rear surface of the cylinder block 13, and the starter motor 44 is disposed in the concave shape 43. If the cylinder block 13 is rearwardly inclined, it will interfere with the rear starter motor 44 as it is. The starter motor 44 can be disposed efficiently with respect to the concave shape 43 on the rear surface of the cylinder block 13 without being shifted backward. In addition, when forming the concave shape 43, it is possible to form appropriately on the rear surface of the cylinder block 13 using a placement core.

If the starter motor 44 is shifted rearward, the distance between the output shaft 44a of the starter motor 44 and the crankshaft 11 increases, and the number of idle gears 49 and the like connecting them increases. On the other hand, according to the present invention, the starter motor 44 can be arranged using the concave shape 43 without increasing the number of components.
In the present invention, the cylinder block 13 is integrated with the crankcase 12, and the rigidity of the crankcase 12 can be effectively increased. If the cylinder block 13 is separate from the crankcase 12, the rigidity of the crankcase 12 is reduced compared to the case where the cylinder block 13 is integrated, resulting in problems such as increased noise, mechanical loss, and increased weight. obtain.

Furthermore, in the present invention, a breather chamber 45 is provided behind the starter motor 44 so as to be integrated with the upper case 28 of the crankcase 12.
In the arrangement relationship between the starter motor 44 and the breather chamber 45, if the starter motor 44 is shifted rearward, it is difficult to secure the capacity of the breather chamber 45 as it is. On the other hand, if the breather chamber 45 is shifted rearward in correspondence with the starter motor 44, the layout relationship between the parts may be adversely affected and the layout relationship of the parts may be impaired. In the present invention, as described above, by utilizing the concave shape 43 and arranging the starter motor 44 efficiently in a space without being shifted rearward, it is possible to ensure and maintain an appropriate layout property of surrounding components.

As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
Although an example in which the engine 10 is a parallel 4-cylinder engine has been described in the above embodiment, the number of cylinders can be increased or decreased as appropriate. Further, the rearward tilt angle of the cylinder axis Z can be appropriately set according to the engine specifications or the vehicle type.

DESCRIPTION OF SYMBOLS 10 Engine, 11 Crankshaft, 12 Crankcase, 13 Cylinder block, 14 Cylinder head, 15 Cylinder head cover, 16 Oil pan, 17 Transmission case, 18 Exhaust pipe, 19 Muffler, 20, 21 Junction part, 22 Collecting pipe, 24 Radiator 25 Water pump, 26 Oil filter, 28 Upper case, 29 Lower case, 30 Crank chamber, 31 Counter shaft, 32 Crank web, 33 Journal part, 34 Journal bearing, 35 Connecting rod, 37 Primary drive gear, 38 Primary driven gear, 39 clutch device, 40 drive shaft, 41 drive sprocket, 42 water jacket, 43 concave shape, 44 starter motor, 44a output shaft, 4 Breather chamber, 46 breather chamber cover 47 torque limiter, 49 idle gear, 50 one-way clutch, 100 motorcycle.

Claims (4)

A four-cycle multi-cycle equipped with a crankcase divided into an upper case and a lower case, a cylinder block integrated with the crankcase, and a crankshaft and a transmission input shaft that are pivotally supported on mating surfaces of the crankcase A cylinder engine,
With respect to a perpendicular line passing through the crankshaft from the extension line so that an extension line connecting the respective center axes of the crankshaft and the transmission input shaft and a cylinder axis line of the cylinder block intersect at an acute angle in an engine side view A four-cycle multi-cylinder engine characterized in that the cylinder block is inclined rearward. The cylinder axis of the cylinder block is below the water jacket on the rear surface of the cylinder block and is perpendicular to the mating surface of the crankcase from the rear edge of the mating surface of the cylinder block with the cylinder head. the concave shape recessed on the side provided, four-cycle multi-cylinder engine according to claim 1, wherein placing the starter motor to the concave shape.   The four-cycle multi-cylinder engine according to claim 2, wherein the concave shape is provided substantially in the center in the engine width direction.   The four-cycle multi-cylinder engine according to claim 2 or 3, wherein a breather chamber is provided integrally with the upper case behind the starter motor.

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